Manufacturing electronic components requires extremely complex methods. Furthermore, manufacturing such components requires a complex and expensive infrastructure, such as foundry plants for manufacturing the integrated circuits of these electronic components from silicon and based on masks.
The miniaturization of transistors in the method for manufacturing the integrated circuits has made it possible to produce integrated circuits that are faster, less energy-consuming and less costly for one and the same function. However, this technique reduces the reliability of the transistors and, de facto, the overall reliability of the integrated circuit.
The reliability of integrated circuits may vary depending on the technology that is used. For example, the function performed by the integrated circuit with 28 nm manufacturing technology may fail earlier during use thereof than with 40 nm technology or another more obsolete technology (65 nm for example). Moreover, the lifetime of electronic products has a tendency to diminish as miniaturization progresses. This tendency is a major obstacle for embedded electronic systems, for example in the field of the motor vehicle industry, the avionics industry or else the defense industry. Such embedded systems are not able to benefit from the advantages of miniaturization to improve their performance, which may limit competitiveness in such fields. Specifically, the reliability level of integrated circuits on thin technologies (for example 28 nm) is below the requirements stipulated by certification authorities and modern standards.
The reduction in the reliability of the integrated circuits is due to the combination of physical phenomena and chemical phenomena that occur in the transistors of the integrated circuits. Such phenomena lead to a variation in the electrical parameters, which has a tendency to reduce the switching speed of each transistor. This slowing is reflected in the delayed propagation of the information signals, which may ultimately result in the information bits being altered. Such an alteration may cause failure of the integrated circuit: the integrated circuit then no longer correctly performs the desired function (for example malfunctioning of the braking operation of a vehicle).
The occurrence of these physical and chemical phenomena in the transistors depends on several variables: the geometry, the materials used, the design of the pattern, the supply voltage and the junction temperature of the transistor, the sequence and the alternating frequency of the bits (between a bit of value 0 and a bit of value 1) that pass through the transistor. The overall reliability of the integrated circuit also depends on the way in which the transistors are interconnected.
The reliability problem with the transistors is generally addressed by the semiconductor manufacturer of the integrated circuit. However, the reliability problem is nowadays a major constraint in the design phase of integrated circuits. In the known approaches, the designer uses software tools that are capable of providing a preliminary indication as to the reliability level of the integrated circuit, before manufacture thereof. However, such tools require the use of a database that contains technological constants. These technological constants are dependent on the geometry, on the materials used, on the design of the pattern, on the supply voltage and on the temperature of the transistor. They are essential for obtaining an accurate estimation of the reliability level.
The content of these databases is generally obtained empirically by the manufacturer using internal testing means. Such a database is not available to all semiconductor manufacturers. Moreover, this information is confidential in nature, such that access thereto is greatly limited (access under license, access limited to third parties who outsource the manufacture of only their IC, etc.).
Furthermore, the database is not complete, as constructing it requires a very lengthy process of characterizing each type of transistor. Generally, the manufacturer constructs this base for a few typical cases. However, integrated circuit designers need to know the impact of a design choice—for example an IP processor X rather than a processor Y—on the risks of the integrated circuit being developed, regardless of the technology used.
Besides the influence of the design choices, the risks to the integrated circuit are also influenced by the mission profile contemplated by the end user of the IC. The mission profile represents the intended operating conditions of the integrated circuit during use thereof in the end system. A mission profile is notably characterized by the following parameters: the operating period during which the integrated circuit is powered, the supply voltage of the integrated circuit, the internal temperature of the integrated circuit and the manufacturing technology for the integrated circuit.
To date, there are no design solutions outside of manufacturing plants that allow the designer internally and accurately to analyze the impact of a technology on the overall reliability of his application-specific integrated circuit.
Patent application US2012/0245879A1 describes a programmable test bench for characterizing a process for manufacturing an integrated circuit, and notably the electrical properties of a transistor. This test chip may be used before an integrated circuit is manufactured by a design engineer. The test bench includes a test slice of semiconductor material (a die) that contains devices under test (DUT) of transistor type and embedded test and measurement electronics. This reference integrated circuit is designed, manufactured and sold by the provider of the test bench. The test bench may be configured by a user to launch the characterization and recover the measurement results. The results are stored in the form of a file in the machine. This solution makes it possible to characterize the variations in and the reliability of the process for manufacturing the circuit for various mission profiles. However, this solution requires reliability expertise to configure the test bench, whereas design engineers do not generally have such expertise. Moreover, this solution does not make it possible to directly estimate the impact of a design choice for the integrated circuit on the reliability thereof. Specifically, the measurement outputs of the test bench are not able to be exploited so as to make such an estimation.
There is therefore a need for a system and a method for testing an integrated circuit in the design phase.